1. Field of the Invention
The present invention relates generally to material handling equipment and, more particularly, to a dual-piston pump or the like presenting an angled pump chamber and piston arrangement for assisting in operation and clean-up of the apparatus, and including a construction that permits the components of the apparatus to be easily broken down for cleaning.
2. Discussion of the Prior Art
Food processors often make use of large pumps for pumping and/or portioning of comestible products such as meat or vegetables. One class of food pump of this character which has achieved substantial commercial success is the twin piston food pumps commercialized by Marlen Research Corporation of Overland Park, Kans. Exemplary pumps of this type are illustrated in U.S. Pat. No. 4,869,653 which is incorporated by reference herein.
Generally, a conventional pump includes a pair of side-by-side assemblies supported on a frame in communication with a pump chamber to which comestible products are supplied. The pump chamber is defined by a front wall, a rear wall, and a side wall extending therebetween. Each assembly includes a sleeve that is movable in a horizontal direction through the chamber between a retracted position in which an end of the sleeve is moved to within one or two inches of the rear wall of the chamber, and an extended position in which the end of the sleeve engages the front wall. A piston is also provided for each assembly, and is supported within the sleeve for independent reciprocating movement relative to both the sleeve and the pump chamber.
Because the sleeves and pistons in the conventional construction are supported for reciprocating movement in a horizontal plane, and the pump chamber is shaped to accommodate this movement, it is difficult to obtain complete drainage of cleaning fluid from the apparatus during a clean-up operation. Rather, cleaning fluid introduced into the chamber and sleeves settles along the bottom thereof, preventing complete cleaning of these surfaces.
Another known construction for a pump apparatus includes a vertical sleeve and a piston supported in the sleeve for reciprocating movement. In this known construction, the piston is provided with a face that is angled relative to vertical such that no flat horizontal surfaces are provided on which the cleaning fluid may settle. However, comestible product is allowed to stick to the top of the piston during the entire pumping operation, and may become stale if the apparatus is not cleaned frequently enough.
In order to permit cleaning of the pistons of a conventional pump, it is known to provide a piston assembly including a removable face. A snap ring or other fastener is provided to hold the face in place on the piston during normal operation, and may be removed to permit removal of the face. However, such fasteners represent additional parts that must be separately cleaned, and are susceptible to being lost.
Another aspect of known dual-piston pumps resides in the provision of a construction in which the pistons are physically prevented from being extended beyond the ends of the sleeves, either during operation or clean up. This design insures that the piston will not pass completely through the sleeve and allow product in the pump chamber to blow back through the sleeve. However, this feature of the known design renders clean-up of the pistons and sleeves difficult, and restricts access to these parts of the apparatus.